LIGHTING SYSTEM Low Beam Headlight Circuit

DESCRIPTION

The main body ECU (multiplex network body ECU) controls the low beam headlights.

WIRING DIAGRAM


  1. for HID Headlight:

    A01G96YE10

  2. for Halogen Headlight:

    A01G85LE10

INSPECTION PROCEDURE

Note


  • Inspect the fuses and bulbs for circuits related to this system before performing the following inspection procedure.

  • If the main body ECU (multiplex network body ECU) is replaced, refer to Service Bulletin.

PROCEDURE


  1. PERFORM ACTIVE TEST USING GTS


    1. Connect the GTS to the DLC3.

    2. Turn the engine switch on (IG).

    3. Turn the GTS on.

    4. Enter the following menus: Body Electrical / Main Body / Active Test.

    5. Check that the relay operates.

      Main Body
      Tester Display Test Part Control Range Diagnostic Note
      Headlight Relay Headlight relay (Low beam headlights) ON/OFF -
      OK
      Headlight relay operates. (Low beam headlights illuminate.)

    NG

    INSPECT H-LP RELAY Click here

    OK

    PROCEED TO NEXT SUSPECTED AREA SHOWN IN PROBLEM SYMPTOMS TABLE Click here

  2. INSPECT H-LP RELAY


    1. Remove the H-LP relay from the engine room relay block and junction block assembly.

    2. A01G55BE01

      Measure the resistance according to the value(s) in the table below.

      Standard Resistance
      Tester Connection Condition Specified Condition
      3 - 5 Voltage not applied between terminals 1 and 2 10 kΩ or higher
      3 - 5 Voltage applied between terminals 1 and 2 Below 1 Ω

    NG

    REPLACE H-LP RELAY

    OK

  3. CHECK HARNESS AND CONNECTOR (H-LP-MAIN FUSE - H-LP RELAY)


    1. Measure the voltage according to the value(s) in the table below.

      Standard Voltage
      Tester Connection Condition Specified Condition
      Relay terminal 2 - Body ground Always 11 to 14 V
      Relay terminal 5 - Body ground Always 11 to 14 V

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  4. CHECK HARNESS AND CONNECTOR (H-LP RELAY - HEADLIGHT ASSEMBLY LH AND HEADLIGHT ASSEMBLY RH)


    1. Disconnect the A19*1 or A17*2 headlight assembly LH connector.

    2. Disconnect the A52*1 or A50*2 headlight assembly RH connector.

    3. Measure the resistance according to the value(s) in the table below.

      Standard Resistance
      *1:
      Tester Connection Condition Specified Condition
      Relay terminal 3 - A19-3 (LO) Always Below 1 Ω
      Relay terminal 3 - A52-3 (LO) Always Below 1 Ω
      Relay terminal 3 - Body ground Always 10 kΩ or higher
      *2:
      Tester Connection Condition Specified Condition
      Relay terminal 3 - A17-2 (LO) Always Below 1 Ω
      Relay terminal 3 - A50-2 (LO) Always Below 1 Ω
      Relay terminal 3 - Body ground Always 10 kΩ or higher

      • *1: for HID Headlight

      • *2: for Halogen Headlight


    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  5. CHECK HARNESS AND CONNECTOR (H-LP RELAY - INSTRUMENT PANEL JUNCTION BLOCK ASSEMBLY)


    1. Disconnect the 3D instrument panel junction block assembly connector.

    2. Measure the resistance according to the value(s) in the table below.

      Standard Resistance
      Tester Connection Condition Specified Condition
      Relay terminal 1 - 3D-12 Always Below 1 Ω
      Relay terminal 1 - Body ground Always 10 kΩ or higher

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  6. INSPECT INSTRUMENT PANEL JUNCTION BLOCK ASSEMBLY


    1. Remove the instrument panel junction block assembly Click here.

    2. A01G8GVE27
      Text in Illustration
      *a

      Component without harness connected

      (Instrument Panel Junction Block Assembly)

      Remove the main body ECU (multiplex network body ECU) from the instrument panel junction block assembly.

    3. Measure the resistance according to the value(s) in the table below.

      Standard Resistance
      Tester Connection Condition Specified Condition
      3D-12 - MB-15 (HRLY) Always Below 1 Ω
      3D-12 - Body ground Always 10 kΩ or higher

    NG

    REPLACE INSTRUMENT PANEL JUNCTION BLOCK ASSEMBLY Click here

    OK

    REPLACE MAIN BODY ECU (MULTIPLEX NETWORK BODY ECU) Click here